1. Field of the Invention
The present invention relates to a digital terrestrial broadcasting, and more particularly, to a method and an apparatus for transmitting additional data in a digital terrestrial broadcasting system.
2. Related Art
In accordance with the development of a digital broadcasting service, there is a need to additionally transmit various data as well as simply transmitting video and audio. That is, in order to additionally provide a supplementary service in addition to a basic service, additional data may be defined and transmitted. As application services utilizing the additional data, a three-dimensional (3D) video service in which a left video is defined as a basic service and a right video or depth data is defined as a supplementary service, an ultra high definition (UHD) service in which high definition (HD) video quality is defined as a basic service and a UHD video quality is defined as a supplementary service, a data service connected with a video service, an electronic program guide (EPG), and the like, may be provided. In additionally providing the supplementary service, it is necessary to have backward compatibility with the terrestrial broadcasting system according to the related art. That is, a new terrestrial broadcasting system providing the supplementary service and the terrestrial broadcasting system according to the related art needs to be compatible with each other.
Meanwhile, in the case of the digital broadcasting system according to the related art, broadcasting stations unilaterally broadcast broadcasting programs to all users, and a user views a desired broadcasting program among the broadcasting programs broadcasted by the broadcasting stations by selecting a desired channel. In addition, a digital cable broadcasting system provides a return channel. The broadcasting station may provide a broadcasting program, data, or the like, requested by a specific user to the specific user through the return channel. However, since a digital terrestrial broadcasting system does not have the return channel, it is difficult to provide a broadcasting program, data, or the like, requested by a specific user to the specific user. Therefore, a current digital terrestrial broadcasting system has used a separate communication network, Internet network, or the like, as a return channel.
In the case of transmitting additional data while having backward compatibility with the digital broadcasting system according to the related art, at least two transmitters transmit the same present broadcasting program and the same additional data. When a specific user requests a broadcasting station server for additional data through a separate communication network, Internet network, or the like, and a plurality of transmitters transmit the additional data, the same present broadcasting program and the same additional data are included even in broadcasting signals corresponding to different broadcasting areas. That is, even a transmitter within a broadcasting area in which the specific user is not included transmits the same additional data, such that efficiency is deteriorated.
Therefore, a need exists for a method for efficiently transmitting additional data requested by a user.